Electrical power meters are known in the art, as illustrated by a rotating disc multielement polyphase meter disclosed in U.S. Pat. No. 4,083,000 to Becker, assigned to the assignee hereof. Such meters are used for measurement of various electrical quantities, and more specifically for measurement of electrical power consumption.
However, although functioning quite well, such meters are limited in function and applicability. More specifically, a particular meter may typically be used only with one type of electrical service, unless a complex power supply is provided therefor. Further, once a decision is made with respect to including or excluding a particular functional option from a design of a particular meter, the configuration is determined and is essentially invariable.
For example, if it is determined that a particular meter is to determine power consumption only as a demand register, modification to a time-of-use register is expensive. If the meter is provided with a time-of-use register, conversion to operation as a demand register is similarly expensive.
Similarly, modification of a polyphase power meter to single phase measurement, or vice versa, cannot be done simply and without substantial effort. Thus, the entire meter must be replaced if the electrical service is changed.
However, present operating preferences of many utility companies are in a state of flux. For example, many utilities are converting from a demand measurement of power consumption to a time-of-use, or to a combined demand and time-of-use, measurement. At this time, some utilities are at an investigation level with respect to making such changes.
With the measuring meters available in the prior art, such conversions are quite expensive since, in addition to replacement of older meters, a conversion will also require replacement of new meters which may have only recently been installed to replace defective meters.
Further, when contemplating purchases of power measurement meters, the users must know in advance each of the features desired to be incorporated in the meter, since changes in meter functions, if possible, are difficult and expensive. Accordingly, a dis-incentive exists for users to upgrade the measurement equipment being used since it is difficult to predict in advance the options which may be needed at a distant time in the future.
Thus, utility companies are faced with an undesirable expense whenever selecting new metering equipment, as well as when contemplating a conversion in the method of power measurement.
Another difficulty with meters of the prior art relates to the time consumptive nature of assembly thereof, since the various elements of the measurement equipment are required to be individually mounted and connected. Thus, assembly, maintenance, or repair of prior art meters is time consumptive and thus expensive.
In recent meter design, the use of electrical registers has been advocated, either to replace or supplement the existing mechanical registers. However, even in the more recent designs, there has been provided only a single structural component which may be "plugged in" for assembly.
More specifically, in such a design a single electronic module is provided, wherein the entire meter movement, including display, power supply and transformer, function circuitry, and the like, is provided in a single module. Thus, replacement of a defective meter is made easier, in that the entire meter may be easily replaced. However, such an arrangement, while somewhat easing the maintenance process, fails to address the above described deficiencies of the prior art, particularly pertaining the modification of capabilities of a meter, maintenance, repair and assembly.
There is thus a need in the prior art for measuring devices which may be provided with varying functional capabilities as needs change, to permit upgrading and modification of existing meters.
Specifically, there is a need for meters which may be converted from one form of measurement of consumption to another form, such as from demand to time-of-use or vice versa, without requiring the entire meter to be discarded and replaced.
Additionally, there is a need in the prior art for meters which may be modified for operation on different electrical power sources without requiring complete replacement of the entire meter assembly.
Moreover, there is a need for a simplified measuring apparatus having replaceable, interchangeable modular parts which are easily assembled to form the meter.